1. Field of the Invention
The present invention relates to fitness machines and more specifically, to the motor and inertia flywheel arrangement of a fitness machine.
2. Description of the Related Art
FIG. 1 illustrates a motor and inertia flywheel arrangement installed in a treadmill 10. As illustrated, the motor 11 has a motor shaft 12 extended out of the front side and mounted with an inertia flywheel 13 that keeps the rotation of the motor shaft 12 in balance. The inertia flywheel 13 has a belt wheel 14 fixedly provided at the front side and coupled to the drive member of the tread base of the treadmill 10 through a transmission belt 15. The motor 11 produces heat during operation. Accumulation of heat will lower the working efficiency of the motor 11, or may cause the motor 11 to burn out. Therefore, heat must be quickly carried away from the motor 11 during operation of the treadmill 10. According to this design, a fan 6 is fastened to the rear end of the motor shaft 12 for drawing outside currents of air into the inside of the motor 11 during rotation of the motor shaft 12. However, because the inertia flywheel 13 is provided at the front side of the motor 11, it hinders the flowing of the flow of air A passing through narrow gap S in between the rotor 17 and stator 18 of the motor 11, thereby producing a back pressure or causing the flow of air A to change into a turbulent flow. The back pressure or turbulent flow reduces the heat dissipation efficiency of the fan 14 and increases the load to the motor 11, thereby shortening the service life of the motor 11.